phragle

iTrader: (3)

Wait...you are expecting 450/500 hp when the motor is redone, and. your wonder why it currently doesnt want to spin a 25p prop to 5500 rpm now. You also state your seeing 68mph now.. Having a 22 foot 24 degree boat myself, that sounds about spot on for a small block making 350-400hp now. With a 330 I saw 60, with 650 and a raised X I have seen 83 Your expectations may be a bit out of alignment.

Donnie D

I guess we will all find out next season. I haven’t had this boat very long. I’ve been out of boating since the early 90s so I’m feeling my way back in to the boating scene. Im speaking to some very knowledgeable people to help me along with this project. I’m not much will projections so I’ll just wait and see what the new combination does on the dyno and how the boat reacts once the new power is installed. Thanks for your opinion and we shall see how close you are next year when the boat comes back out.

Ryan00TJ

iTrader: (8)

My 21' Hammond Challenger was similar to your 22. Both pad bottom light hulls.
My 385ci
AFR 190R heads 10-1 static
Cam Motion 234/240 .580/.568 112+4
Portmatched RPM Airgap
Dry to transom exhaust
Holley 750HP
475-500hp estimated

Ran 77-78 anytime. 79-80.5 best conditions
5800-6100rpms. Labbed 22p Hydro QIV

That cam is rather small IMO for your goals.

Donnie D

What gas do you run in that boat? Tony Bischoff wants the new engine to end up with 10-1 compression. He also stated that the cam we are planning on using was a little aggressive, but would be a good choice. Honestly I don't have any etched in stone goals other than for the boat to be reliable and not be a complete and total pig. Other than that I just want something my wife and I can go out and have fun in. It will never be an off shore boat, and it will never be a 80 MPH plus boat as it will only see lake and river use. It won't be continuously romped on. Just a blast across the lake or down the river from time to time. I really want to bring this boat back to what it once was with the only difference is for it to run much better than it did when delivered with it's 260HP Mercruiser power which I've been told by the original owner the boat ran 66 MPH with that combination. If the boat will run 70-75 MPH honestly...I'll be happy with that.

phragle

iTrader: (3)

Just keep in the back of your mind, things that are nothing in a 22' boat at 60 start to be rather intersting at 70, by the time you get to 80, interesting can become puckering really fast. But it is fun flying by some bigger "fast" boats....

SB

iTrader: (1)

This is what's needed below. You'll need 230* at .050" or more to get 475-500hp.
As a note: 218 at .050" flatlines (HP stays flat) in power around 5200rpm in a 350. 5k in a 383. Many builds and small single engine boats with decent heads show this

Donnie D

This is not my first Velocity or fast boat. I've had a 23 and a 30. I also was an operator of the Cincinnati Fire Department Fire/Rescue boat. Though I've been out of boating for a while. I grew up boating on the Ohio River.

hogie roll

unlikely with those heads, a baby cam, and boat exhaust. The mystery compression ratio is a concern too

Ryan00TJ

iTrader: (8)

Marina 89 fuel. FR2lS plugs and 78/88 carb jetting. Bischoff is being conservative on the cam specs. You would need to modify your exhaust to go much bigher than his cam spec.

tommymonza

My 18 foot Baron is a 58mph boat with a 260 merc, I have ran with a lot of stock Merc 260 boats in the past, 18 Donzis and 21Scarabs back in the day.

All were about dead even for speed at 58mph..

Back when we built them we spent a day with Mercury and a trailer full of props and a radar gun trying to figure why the 280/trs boat was so much slower than the other ones we built that were 260/Pre alpha Mr drives.

260/mr boat 58 on radar.
280/Trs boat 55 on radar.

I think your 66mph with a stock 260 merc was a optimistic Tale.